Driving apparatus for hoist pan

ABSTRACT

A material handling system for vibratory finishing or grinding mills into which are placed materials and abrasive media and wherein the materials are operated upon. In a finishing mill the materials are parts which are finished, polished, or deburred, and in a grinding mill the materials usually are chemicals which are reduced in size. The system includes a vibratory mill into which such materials and media are placed, a vibratory screen separator for separating the materials from media after completion of the operation thereon, a hoist pan for handling the media or material and media, and a jib hoist system for moving and positioning the pan. Media or material and media are loaded into the pan, and same is lowered to the top of the finishing machine causing the load to be evenly dumped into the finishing machine. After the finishing operation, the material may be moved or transported in any suitable manner to any further operation stage, and the media is returned to the hoist pan. A pan driving mechanism is provided for rotating the pan as the media is supplied thereto from the separator or mill such that the pan is evenly loaded. Several bottom-dumping pan configurations are disclosed which provide a relatively even discharge of the media into the mill when the pan engages the mill.

United States Patent 51 June 27, 1972 Denight et a1.

[54]- DRIVING APPARATUS FOR HOIST PAN [72] Inventors: James P. Denlght,Cincinnati; George A.

Burgess, Fairfield, both of Ohio [73] Assignee:. Sweco,1nc., LosAngeles, Calif.

[22]. Filed: May 19, 1969 [21] Appl. No.: 825,861

[52] U.S. Cl. ..241/101 R, 241/171, 214/340 [51 Int. Cl. ..B02c 19/00,365g 7/00 [58] Field of Search ..241/109, 171, 186, 202, 222,

241/245, 248, 265, 271, 284, 301, 101 R; 214/340, 741,18 R, 18 G, 18 D,18 V, 28, 32; 74/721, 209, 210, DIG. 4; 335/302, 306; 141/280, 281, 283;

Primary Examiner-Andrew R. Juhasz Assistant Examiner-Gary L. SmithAtt0rneyLy0n & Lyon 57 ABSTRACT A material handling system for vibratoryfinishing or grinding mills into which are placed materials and abrasivemedia and wherein the materials are operated upon. In a finishing millthe materials are parts which are finished, polished, or deburred, andin a grinding mill the materials usually are chemicals which are reducedin size. The system includes a vibratory mill into which such materialsand media are placed, a vibratory screen separator for separating thematerials from media after completion of the operation thereon, a hoistpan for handling the media or material and media, and a jib hoist systemfor moving and positioning the pan. Media or material and media areloaded into the pan, and same is lowered to the top of the finishingmachine causing the load to be evenly dumped into the finishing machine.After the finishing operation, the material may be moved or transportedin any suitable manner to any further operation stage, and the media isreturned to the hoist pan. A pan driving mechanism is provided forrotating the pan as the media is supplied thereto from the separator ormill such that the pan is evenly loaded. Several bottom-dumping panconfigurations are disclosed which provide a relatively even dischargeof the media into the mill when the pan engages the mill.

6 Claims, 14 Drawing Figures PATZNTEDJUH 27 19. 2 3.572, 581

sum 2 OF 5 INVENTORS J4M5 9 DEV/6177 i Y 660265 4 5025655 DRIVINGAPPARATUS FOR IIOIST PAN said applications being assigned to theassignee of the present application.

The present invention relates to vibratory mills and a material handlingsystem therefor, and relates more particularly to a magnetic drivingarrangement for hoist pans used in such systems.

Although applicable to both finishing and grinding mills, the conceptsof the present invention will be described with reference to finishingmills. Various types of finishing mills have been in use for a number ofyears for finishing, polishing and deburring. An example of theconstruction of a mill of this type is disclosed in Podmore et al. U.S.Pat. No. 3,100,088. This type of mill includes an annular bowl intowhich is loaded parts and abrasive media. Examples of such parts arecastings of metal, plastic parts, and so forth. The mill may include asource of vibratory energy such as that described in Meinzer U.S. Pat.No. 2,284,671.

Conventionally, the media or parts and media are loaded into the millmanually. This has been accomplished through the use of a rectangularmedia receptacle having an opening at one end and suspended from anoverhead hoist. Usually, two men, one holding the front end of thereceptacle down while the other pushes the rear end of the receptacle upare necessary in order to redistribute the media load in the pan from acarrying to a pouring position. The mill operator must be present inorder to load the media into the mill, and the load media into thereceptacle so as to properly distribute the media load in the receptacleto prevent uneven distribution thereof. It will be readily apparent thatthere are a number of disadvantages to media handling in this manner,not the least of which is the lack of ability to automate theoperational steps required, and the complete reliance upon the adeptnessof the men involved. Also, media generally is handled by bucketconveyors from which it is difficult to remove all media when it isdesired to change to a different media. Consequently, undesirable mixingof different media can occur.

Although by employing a round pan which can evenly load material intothe mill, it is necessary that the material be loaded evenly into thepan prior to dumping thereof into the mill.

Accordingly, it is a principal object of this invention to provide anovel drive system for a round hoist pan used in a material handlingsystem for vibratory mills.

Another object of this invention is to provide a novel magnetic drivesystem for rotating a round pan so as to allow even loading of materialinto the pan for subsequent dumping thereof into a vibratory mill.

These and other objects and features of this invention will becomebetter understood through a consideration of the following descriptiontaken in conjunction with the drawings in which:

FIG. 1 is a perspective view of a material handling system for vibratorymills according to the present invention;

- FIG. 2a is a simplified plan view of a drive arrangement for the roundhoist pan used in the system of FIG. 1;

FIGS. 2b and 2c respectively are plan and elevational views of the panand drive system;

FIG. 3 is a fragmentary view of an end of a stabilizer arm forsupporting the hoist pan;

FIGS. 4a through 40 illustrate in more detail an embodiment of a roundhoist pan having an opening bottom for dumping material into thevibratory mill;

FIG. 5 is a partial view of another embodiment of a round hoist pan;

FIGS. 6a through 6c illustrate a further round hoist pan embodiment; and

FIGS. 7:: and 7b illustrate an alternative and portable drivearrangement for the round hoist pan.

Turning now to the drawings, FIG. 1 illustrates a media handling systemfor vibratory mills incorporating the concepts of the present invention,and includes a vibratory finishing mill 10 of conventional constructionhaving a toroidal chamber 11 into which parts and abrasive media areplaced and vibrated such that the parts are finished, polished,deburred, and so forth. This mill may be, for example, a Model FM-IOmill manufactured by SWECO, Inc., of Los Angeles, California. Theabrasive media or, parts and media if desired, is handled by a roundhoist pan 12 which is supported, moved and positioned by a stabilizerarm 13 of a jib hoist or bridge crane system 14. The pan 12 is moved andcentered above the machine 10 to dump the load within the pan into thebowl 11. After the finishing operation is completed, the parts and mediaare discharged through a chute 15 onto a vibrating screen separator 16to separate the parts from the media. If the parts are of a metalsusceptible to magnetic attraction, a moving belt magnetic separator 17may be used to retrieve the parts rather than allowing them to dischargefrom an end 18 of the separator 16. The separator 16 includes a mediadischarge chute 19 for allowing the media to be returned to the pan 12when it is moved to the dotted line position 20 as seen in FIG. 1. Theseparator 16 is of conventional construction and includes a screenhaving a mesh size for allowing media to fall therethrough and intodischarge chute 19, the mesh size being small enough to retain the partsfor movement thereof to the discharge end 18 of the separator 16.Alternatively a mill having its own separating means may be used withoutrequiring the use of a separate separator 16.

As will be described subsequently, a drive system 21 is provided torotate pan 12 when itis in the position 20 during discharge of the mediafrom the chute 19 to evenly distribute the media in the pan. Rotation ofthe pan during loading thereof causes the material fed thereto to beevenly distributed therein. Uneven distribution of material would causethe pan to hang unbalanced and create difficulty in transporting,positioning and dumping the pan, and discharge of material into the millwould be uneven. The drive system may be a friction drive such as a typeemploying a rubber surfaced wheel, but preferably is a magnetic drivesystem as described subsequently.

The separator 16 preferably includes different mesh screens such thatreusable media can be separated from broken or chipped media, the latterbeing discharged through a chute (not shown). After the pan 12 has beenreloaded with media from the separator 16, it may be suitably stored onthe floor, in a rack, stacked with other pans, or again discharged intothe mill 10 with a new load of parts. Additionally, the reloaded pan maybe discharged into another mill of the nature of the mill 10 by the jibhoist system 14, or by another hoist system such as a bridge cranesystem. Another pan with a different size or type media may be picked upby the jib hoist system 14 and used with the mill 10. Thus, it will beapparent that various combinations of pans, media types and sizes,mills, and so forth may be incorporated into the system of FIG. 1.

Turning now to a more detailed discussion of the apparatus illustratedin FIG. 1, the finishing mill 10, as noted earlier, is a conventionalunit. This mill 10 includes a base 25 from which is supported the bowl11 by resilient members, such as springs (not shown). A vibratory sourceis mounted within the mill and coupled with the bowl to vibrate thesame. The bowl includes a center column 26 which has been modified toinclude a cover 27 having a projection 28. The projection, as will bedescribed subsequently, serves to open the bottom of the pan 12 to causedischarge of the material contained therein evenly into and around theinterior of the bowl 11.

The jib hoist system 14 includes a stationary base 30 which is freestanding or affixed in any suitable manner to the base 25 of the mill,such as by a pair of plates welded to both bases, or affixed to theseparator base. The base 30 is provided with a vertical pivot or kingpin 31 which supports a vertical column member 32 of the crane forrotation to allow proper positioning of the pan 12. A horizontal beam 33is affixed to the upper end of the member 32 to support a hoist or winch34 by means of a hook 35. A counterbalance 36 may be provided. A chain37 is coupled between the winch 34 and a support bracket 38 on the outerend of the stabilizer arm 13. The bottom 39 of the bracket 38 has a slot40 therein perpendicular (note FIG. 1) or angled (note FIG. 3) withrespect to the arm '13 for receiving and supporting the pan 12 as willbe described subsequently. The inner end of the arm 13 is coupled to apair of flange members 43 and 44 which are coupled together by a pair ofplates and encircle the support member 32. Rollers are provided on theinner sides (note FIG. 2b) of these flange members to allow thestabilizer arm to roll up and down the member 32 as the winch 34 isoperated. A handle 45 is provided for rotating the hoist system aboutthe pivot 31 to allow the. pan 12 to be moved to above the mill or toanother closely adjacent mill, to be moved to the dotted line positionfor reloading the pan with media, or for moving the pan to anotherposition where it may be stored, stacked, or the like.

7 The pan has a diameter slightly smaller than the inside diameter ofthe bowl 11..

The vibrating screen separator 16 may be a conventional unit including abase 50 which may be affixed to the base of the mill, and a screeningchamber 51. The screening chamber includes one or more screens and isvibrated by means of a motor and vibratory drive system 52. Thescreening chamber may include an upper coarse mesh screen for enablingthe parts to be separated from the media, and a lower fine mesh screento enable reusable media to be separated from broken and chipped media.The separator may also include a suitable washing system (not shown) forwashing or treating the media and/or parts. As noted earlier, thereusable media is discharged through the chute 19 into the pan. Althoughthe parts may be removed in any convenient manner from the upper screenof the separator, as noted earlier, a magnetic belt separator 17 may beemployed for picking up certain metallic parts.

Considering now the drive system 21 as more completely illustrated inFIGS. 2a through 20, the same includes an electrical motor 60 coupled bya chain 61 to a magnetic roller or rollers 62. An idler 63 maintainsproper tension of the chain 61. One or more of the rollers 62 may beprovided, and a typical roller is 4 inches in diameter. A metal wheel orpulley may be mounted on the motor shaft and directly contact and drivethe rollers 62 thereby obviating the need for a chain drive 61. Thisdrive assembly may be mounted to the overall system in one of severalways; As illustrated in FIGS. 1 and 2a, a support bracket 64 maybeaffixed to the base of the separator 16, or alternatively, may beaffixed to the base 30 of the'crane or to the base 25 of the mill. Achannel member 65 as best seen in FIG. 2a is affixed to the bracket 64,and has extending therefrom a pair of bracket plates 66 and 67. Thesebracket plates may in turn pivotally support a pair of bracket arms 68and 69 for supporting the motor 60 and roller 62 at a pivot 70. A spring71 is coupled between the arm 69 and the bracket 64, and stop plates 72and 73 are respectively affixed to the arm 69 and bracket 64 for aidingin release of the pan from the magnetic drive as will be describedsubsequently.

The magnetic roller or rollers 62 serve two purposes. As the round pan12 is moved into position, the roller pulls the pan into engagementtherewith, and drives the pan. Typically, the pan is driven at a speedof 15 to 20 revolutions per minute to enable uniform distribution of themedia into the pan from the separator. As the pan is being loaded, thereis a tendency for the first gush of media to move the pan off center andaway from the driving roller 62, but this is overcome by the magneticattraction of the roller. Additionally, problems of friction andpressure in driving the pan are eliminated by the use of the magneticdrive. The pan may be separated from the roller by moving the panbackward (clockwise about the pivot 70) thereby extending the retentionspring, and then pulling the pan forward briskly until the stop plates72 and 73 engage such that the momentum of the pan snaps it away fromthe rollers. If desired, discharge of parts or parts/media may be madedirectly from the finishing mill into the pan by physically rearrangingthe drive arrangement such that the pan is properly positioned withrespect to the mill for receiving the material therefrom.

FIGS. 2b and 2c illustrate an alternative arrangement for mounting thedrive assembly 21 wherein the channel member 65 thereof is pivotallysecured to the stabilizer arm 13. The drive assembly may be biasedclockwise as viewed in FIG. 2b by suitable means, such as a spring (notshown) to maintain the rollers 62 against the periphery of the pan 12.In the arrangement of FIG. 2b-2c, the bracket arms 68 and 69 are affixeddirectly to the channel member 65. It will be apparent that the rollers62 illustrated in FIGS. 1 and 2 are journalled for rotation by suitablebearings or bushings.

As noted earlier, the support bracket 38 of the stabilizer arm 13 has aslot 40 in the bottom thereof. This 'slot may have the configurationillustrated in FIGS. 2b and 3 wherein it flares outwardly at 75 toenable the support stud 76 (note FIG. 20) and flange 77 of the pan to beguided into engagement with the arm 13. The bracket may be in the formof a fox as shown in FIG. 1,.or may be open as shown in FIGS. 2b, 2c and3 with sides 78 and 79 and inclined faces 80 and 81 to guide and receivethe flange 77.

FIG. 2b illustrates a flange 77 of one diameter for one size pan, andillustrates the manner in which the flange and support stud 76 may bepositioned in the support bracket 38 at the center line of thestabilizer arm 13. FIG. 3 illustrates the manner in which another sizepan having a larger flange 82 is supported and retained slightly offcenter. This support configuration enables different diameter pans to berotated by the magnetic drive arrangement. The chain 37 from the winch34 may be directly coupled with a hook 84 of the pan, or alternatively,may be coupled near the outer end of the arm 13.

FIGS- 2b and 2c also illustrate in greater detail the manner in whichthe flanges 43 and 44 of the arm 13 are coupled together by means ofplates and 91 and include pairs of upper and lower rollers, only theupper rollers 92 and 93 being seen in the drawings. These rollers bearagainst the faces of the column member 32 to allow the stabilizer arm 13to freely move up and down the member 32 as described earlier.Additionally, a base plate 95 may be provided for supporting the base 30of the jib crane, and may also have secured thereto the bases of thefinishing mill and separator if desired.

Turning now to a consideration of the specific embodiments of the roundhoist pan 12, FIGS. 4a through 40 illustrate a pan 99 which includes alatching-type bottom 100 which is unlatched and caused to open as thebottom of the pan engages the top of the mill 10. This pan includes acylindrical housing or wall 101 with a bottom flange 102, and afrusto-conical insert 103 secured to the housing and flange. A centralcone 104 is provided and is secured at the top thereof by a plurality ofrods 105 extending to the interior wall of the body 101, and near thebottom thereof by a plurality of rods 106 extending to the insert 103.The bottom 100 of the pan 99 comprises a pair of semicircular bottomsegments 107 and 108 which are hinged together by a pin 109 whichextends through the bottom of the central cone 104. A flange 110 may besecured at the top of the housing 101 to reinforce the housing.

The bottom segments 107 and 108 are maintained in their normally closedposition by a pair of latch mechanisms, only the left hand mechanismbeing shown for simplicity of illustration. Each latch mechanismincludes a bolt 112 which releasably engages a bracket 113 affixed tothe respective bottom segment. The bolt is coupled to a release arm 114which is pivoted at 115 by a pair of brackets 116 and 117. As the bottom118 of the arm 114 engages a cam face 119 mounted at the top of the mill10, the bolt 112 is pulled from the bracket 113 allowing the respectivebottom segment to lower as illustrated in dashed lines in FIG. 4a. Thearm 114 is normally biased to close the bolt 112 with the bracket 113 bymeans of a spring 121, and a spring 122 is provided to return the bottomsegments 107 and 108 to their closed positions after the media has beendumped from the pan 99. Latching mechanisms as just described areprovided for both of the bottom segments 107 and 108. It further will beapparent that the construction of the pan 100 dumps the media in asubstantially annular pattern into the interior of the bowl 11 of themill to provide a relatively even distribution of the media around thebowl. No particular configuration is required atthe top of the centercolumn 26 to cause dumping of this pan embodiment.

FIG. 5 illustrates another round pan construction including acylindrical housing 130, a conical insert 131 and a pair ofsemi-circular bottom segments or doors 132 and 133. The central stud 76extends down into the pan and is coupled with the top of a cone 134. Acentral flange 135 is affixed to the inner wall of the housing 130 bymeans of a plurality of radially extending rods 136. A ball thrustbearing 137 is provided, and FIG. 5 shows the configuration thereofwhich is also used with the pan of FIG. 4a. The bottom segments 132 and133 are hinged by a pin 138 in a manner similar to the bottom segments107 and 108 in FIGS. 4a-4b; however, the hinge pin 138 is not coupledwith the cone 134, and the bottom segments 132 and 133 are free to moveup and down with respect to the cone 134. Additionally, a pair ofarcuate guides 139 and 140 are coupled at the inner circular edges ofthe respective bottom segments 132 and 133. When the cone 134 is in itslower position, the central portions of the bottom segments 132 and 133are supported thereon and the outer edges are supported on the insert131, and these segments assume the closed (full-lined) position. Theweight of the media on the segments maintains the bottom of the panclosed. The lower end of the stud 76 extends into a cylindrical guide141 in the cone 134, and the stud and cone are coupled together with apin 142. The pin 142 rides in a slot 143 in the guide. In this mannerthe cone may move freely up and down on the stud 76.

As the pan is lowered to the mill, the bottom of the cone 134 engagesthe cover 27 of the center column of the mill 10 thereby preventing thecone 134 from lowering further, while allowing the body 130 to lower tothe dashed lined position as seen in FIG. 5. This action allows thecentral portions of the bottom segments 132 and 133 at the guides 139and 140 to rise up with respect to the cone 134 because of the momentcaused by the weight of the media at the outer edges of the segments 132and 133 causing the segments to fold, thereby providing a substantiallyannular aperture 144 at the bottom of the pan for discharge of media.After the media is discharged, the pan is raised thereby hereby allowingthe cone to move down and the bottom segments to again assume the flatclosed position. If necessary, the bottom segments m ay be closedmanually.

Alternatively, the center column may include a remotely actuatedmechanism, such as an air cylinder and piston, which can be operated toextend upwardly and engage the actuator of the pan. With thisarrangement, the pan is merely lowered to above the mill and does nothave to be lowered into engagement with the cover 27.

FIGS. 6a through 60 illustrate another configuration of a round hoistpan providing an annular discharge of media. This pan includes a housing150 having a conical insert 151 affixed thereto, and a moving conicalbottom 152. The pan is supported by means of a central bracket 153 whichis secured to the housing 150 by radially extending rods 154. A ballthrust bearing 155 is provided for the support stud 76, and the sametype of bearing is used with the pan of FIGS. 4a and 5. A centralsupport column 157 is rigidly secured to the interior wall of the insert152 by means of rods 158. The movable bottom 152 is affixed to a centralcap 159 which in turn is secured to a stud 160 which extends through thecolumn 157. A spring 161 is provided on the stud and is retained bymeans of an actuator 162 and nut 163. The spring 161 serves to normallybias the actuator 162 and stud 160, and thus the bottom 152, downwardlyto the full-lined position shown in FIG. 6a. When the actuator 162engages the cover of the center column of the mill, the bottom 152 israised to the dashed-line position shown in FIG. 6a to provide anannular aperture 165 for discharge of media evenly into the bowl of thefinishing mill. The bottom of the actuator 162 is above the bottom ofthe pan thus enabling the pan to be placed on a floor for storage orloading without causing the bottom 152 to open. With each of the pansdisclosed herein, resilient gaskets may be used at the edges of themovable bottoms to provide a good seal with the interior sides of pans.

FIGS. 7a and 7b illustrate an alternative arrangement for the magneticdrive for the round pan, the magnetic drive unit being a self-containedand portable unit. This unit includes a pair of base channel members and171 which may be set directly on the floor, or may be mounted on castersas shown. A support column 172 is affixed to the members 170 and 171 forsupporting the magnetic drive assembly. The magnetic drive assembly maybe mounted in a manner similar to that shown in FIGS. 1 and 2a andinclude the spring and stop arrangement for facilitating release of thepan from the magnetic rollers, or may be a fixed arrangement as shown inFIG. 7a and 7b. In the latter arrangement, a bracket 173 for magneticrollers 174 is secured to the column 172 by means of a clamp 175. Thepan 176 is lifted onto a support bracket or holder 177 of a stabilizingarm 178 which also is clamped on the column 172. As is the case with theholders illustrated in FIGS. 2b and 3, the holder is offset at an anglewith respect to the arm 178 and configured to receive difl'erent sizepans having different size flanges (77 or 82) such that the periphery ofthe pan can be properly positioned against the rollers 174. A smallerdiameter pan has a smaller diameter flange (like flange 77 in FIG. 2b),and a larger diameter pan has a larger flange 82. The size of the flangeand configuration of the holder 177 thus determines the position of theperiphery of the pan with respect to the rollers. The diameter of atypical pan at the periphery thereof is approximately 3 feet. As withthe other embodiments, the rollers 174 are driven from a motor and gearbox assembly 180 by means of a chain 181. As shown in FIG. 7a, aplurality of casters also may be affixed to the bottom of the pan 176 toallow the pan to be rolled about. This arrangement is particularlyuseful when no pan rack or stacking facility is available.

As noted earlier, the concepts of the present invention also areapplicable to grinding mills wherein material, such as chemicalcompounds, paint pigments, and so forth, and media are loaded into themill to grind the material, or otherwise reduce the material in size.

What is claimed is:

1. A magnetic drive assembly for driving a hoist pan during loading ofmaterial into said pan in a material handling system from a millcomprising a hoist pan for receiving media which in turn may be dumpedfrom said pan into the finishing chamber of said mill, said pan havingsupport bearing means for supporting said pan for rotation,

magnetic roller means, said magnetic roller means comprising asubstantially circular magnetic roller for engaging a substantiallycircular portion of said pan for rotating said pan,

bracket means for supporting said roller and for maintaining said rollerin a position to engage said pan, and

motor means mounted on said bracket means for rotating said roller.

2. A drive assembly as in claim 1 including a resilient member coupledbetween said bracket means and a support member for said drive assembly,said bracket means and support member having stop means which areengagable upon predetermined relative movement between said bracketmeans and said support member for facilitating release of said pan fromsaid drive assembly.

3. A drive assembly as in claim 2 wherein said support member is mountedadjacent said mill for allowing said pan to be rotated by said driveassembly while being loaded with material discharged from said mill. 4.A drive assembly as in claim 1 including V a support column for saiddrive assembly,

said bracket means being pivotally mounted with respect to said supportcolumn, and a resilient member and stop means mounted between saidbracket means and said support column, said resilient member tending tonormally pivot said bracket means to cause engagement of said stopmeans. i A magnetic drive assembly for rotating a hoist pan duringloading of material into said pan in a material handling system for avibratory finishing mill comprising a hoist pan for receiving mediawhich in turn may be dumped from said pan into a finishing chamber of avibratory finishing mill, said pan having a housing with at least acylindrical peripheral portion and having a support bearing device forallowing rotation of said pan about the central vertical axis thereof,support means for supporting said drive assembly, magnetic roller meansfor engaging said cylindrical portion of said pan housing for rotatingsaid pan, said magnetic roller means comprising a substantiallycylindrical magnetic roller for engaging said cylindrical portion ofsaid p s bracket means coupling said roller with said support means,

arm means for engaging said bearing device of said pan for supportingsaid pan for rotation, said arm means and bracketmeans being disposed tohold said pan such that said cylindrical portion thereof engages saidroller, and

motor means coupled with said roller for rotating said roller.

6. A drive assembly as in claim 5 including a resilient member coupledbetween said bracket means and said support means, said bracket meanspivotally coupling said roller with said support means, said bracketmeans and support means having stop means which are engagable uponpredetermined relative movement between said bracket means and saidsupport means for facilitating release of said pan from said driveassembly.

1. A magnetic drive assembly for driving a hoist pan during loading ofmaterial into said pan in a material handling system from a millcomprising a hoist pan for receiving media which in turn may be dumpedfrom said pan into the finishing chamber of said mill, said pan havingsupport bearing means for supporting said pan for rotation, magneticroller means, said magnetic roller means comprising a substantiallycircular magnetic roller for engaging a substantially circular portionof said pan for rotating said pan, bracket means for supporting saidroller and for maintaining said roller in a position to engage said pan,and motor means mounted on said bracket means for rotating said roller.2. A drive assembly as in claim 1 including a resilient member coupledbetween said bracket means and a support member for said drive assembly,said bracket means and support member having stop means which areengagable upon predetermined relative movement between said bracketmeans and said support member for facilitating release of said pan fromsaid drive assembly.
 3. A drive assembly as in claim 2 wherein saidsupport member is mounted adjacent said mill for allowing said pan to berotated by said drive assembly while being loaded with materialdischarged from said mill.
 4. A drive assembly as in claim 1 including asupport column for said drive assembly, said bracket means beingpivotally mounted with respect to said support column, and a resilientmember and stop means mounted between said bracket means and saidsupport column, said resilient membEr tending to normally pivot saidbracket means to cause engagement of said stop means.
 5. A magneticdrive assembly for rotating a hoist pan during loading of material intosaid pan in a material handling system for a vibratory finishing millcomprising a hoist pan for receiving media which in turn may be dumpedfrom said pan into a finishing chamber of a vibratory finishing mill,said pan having a housing with at least a cylindrical peripheral portionand having a support bearing device for allowing rotation of said panabout the central vertical axis thereof, support means for supportingsaid drive assembly, magnetic roller means for engaging said cylindricalportion of said pan housing for rotating said pan, said magnetic rollermeans comprising a substantially cylindrical magnetic roller forengaging said cylindrical portion of said pan, bracket means couplingsaid roller with said support means, arm means for engaging said bearingdevice of said pan for supporting said pan for rotation, said arm meansand bracket means being disposed to hold said pan such that saidcylindrical portion thereof engages said roller, and motor means coupledwith said roller for rotating said roller.
 6. A drive assembly as inclaim 5 including a resilient member coupled between said bracket meansand said support means, said bracket means pivotally coupling saidroller with said support means, said bracket means and support meanshaving stop means which are engagable upon predetermined relativemovement between said bracket means and said support means forfacilitating release of said pan from said drive assembly.